NOTE: This error is almost always caused because the command does not exist, because the working directory does not exist, or from a windows-only bug.
I found a particular easy way to get the idea of the root cause of:
Error: spawn ENOENT
The problem of this error is, there is really little information in the error message to tell you where the call site is, i.e. which executable/command is not found, especially when you have a large code base where there are a lot of spawn calls. On the other hand, if we know the exact command that cause the error then we can follow @laconbass’ answer to fix the problem.
I found a very easy way to spot which command cause the problem rather than adding event listeners everywhere in your code as suggested in @laconbass’ answer. The key idea is to wrap the original spawn call with a wrapper which prints the arguments send to the spawn call.
Here is the wrapper function, put it at the top of the index.js
or whatever your server’s starting script.
(function() { var childProcess = require("child_process"); var oldSpawn = childProcess.spawn; function mySpawn() { console.log('spawn called'); console.log(arguments); var result = oldSpawn.apply(this, arguments); return result; } childProcess.spawn = mySpawn; })();
Then the next time you run your application, before the uncaught exception’s message you will see something like that:
spawn called { '0': 'hg', '1': [], '2': { cwd: '/* omitted */', env: { IP: '0.0.0.0' }, args: [] } }
In this way you can easily know which command actually is executed and then you can find out why nodejs cannot find the executable to fix the problem.